My tachometer in the Corvette has stopped working and that’s a real shame because the tach is my favorite gauge in any performance car. It’s likely that the plastic drive gear stripped and failed because the cable wasn’t lubricated properly. I haven’t gone in and checked. On a Corvette the tach drives off the side of the distributor housing so at least it’s easy to access! Lots of rain and occasional snow have prevented me from driving it very much lately but hopefully it will warm up and get back into daily usage!